It’s not exactly clear what’s going on at Seattle-based 3Guppies, formerly known as Mixxer, but it definitely doesn’t sound good: apparently the company’s VC backers, VantagePoint Venture Partners, have yanked its $20 million investment, effectively shutting the company down. VentureBeat says VantagePoint “turned off the lights” at 3Guppies and sent its employees home last week, despite it having $8 million left in the bank. Meanwhile, the Seattle PI says the VC firm is negotiating to sell its stake in the company back to its management. 3Guppies’ CEO confirmed to the PI that there were layoffs, but wouldn’t give a specific number, adding that 3Guppies is looking at “strategic alternatives.” 3Guppies’ PR firm and VantagePoint haven’t responded yet to our requests for comment.

3Guppies changed its name from Mixxer in June; before that, it was called 3GUpload. Its initial claim to fame was a service that let users create their own ringtones, but it since has operated in a crowded space of competitors trying to bridge users’ mobile media and social networking sites. It offers a widget that could be used to upload pictures to and download them from MySpace, as well as a content locker and moblogging.

• Mixxer Changes Name, Again: 3Guppies
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• 3GUpload Gets $20 Million Investment; Buys MoPhone